Electric furnace flue gas pure dry purification treatment system and treatment method

Abstract

The invention provides an electric furnace flue gas pure dry purification treatment system which comprises an electric furnace, a continuous preheating device, a mixed combustion settling barrel, a waste heat boiler and a dust remover which are sequentially communicated, the electric furnace is communicated with the mixed combustion settling barrel through a first extraction pipeline, and the continuous preheating device is communicated with the mixed combustion settling barrel through a second extraction pipeline; the waste heat boiler receives high-temperature flue gas output by the mixed combustion settling cylinder, the high-temperature flue gas and cooling water are shunted to complete the heat exchange process, and then the flue gas is converged and input into the bag type dust collector to complete the dust removal process and is discharged from the chimney. According to the invention, the flue gas of the electric furnace is extracted into the mixed combustion settling barrel through the additionally arranged first extraction pipeline, and after the flue gas is mixed with preheated flue gas, the flue gas is retained in the mixed combustion settling barrel for 2-3 seconds under the action of the auxiliary combustor while the temperature of the flue gas is maintained to be greater than or equal to 800 DEG C, so that toxic substances such as dioxin / furan are decomposed, and the mixed flue gas is quenched by the waste heat boiler; the re-synthesis of toxic substances is effectively avoided.

Description

Technical Field

[0001] The invention relates to the technical field of electric furnace fume purification, and in particular to a pure dry purification treatment system and treatment method for electric furnace fume. Background Art

[0002] In order to effectively reduce the flue gas temperature and eliminate toxic substances such as dioxins / furans, the CONSTEEL electric furnace steelmaking high-temperature flue gas purification treatment system currently used at home and abroad is as follows: the high-temperature flue gas generated during the CONSTEEL electric furnace smelting process is passed through the scrap steel preheating (about 450-650℃) → combustion settling chamber → evaporative cooler (rapid cooling) → mixing tower (mixed with roof hood flue gas to reduce flue gas temperature) → bag dust collector (filtration and purification) → fan → chimney discharge.

[0003] However, the existing CONSTEEL electric furnace steelmaking dust removal system has the following disadvantages: 1. The flue gas temperature of the CONSTEEL electric furnace continuous scrap steel preheating system is sometimes low (450-650℃<800℃). As various steel companies pursue the power consumption index of electric furnace steelmaking and the higher scrap steel preheating temperature, the temperature entering the quenching device is generally not high (450-650℃<800℃). Many dioxins are not fully incinerated and decomposed, and are still retained in the flue gas of the electric furnace. The quenching device cannot eliminate these dioxin toxic substances. The use of evaporative coolers (quenching and cooling) + bag-type / cartridge dust collectors to purify the flue gas of the electric furnace cannot reliably and stably remove dioxins from the flue gas, and cannot ensure that the dioxin content in the flue gas discharged by the electric furnace meets the standards.

[0004] 2. In order to ensure that harmful substances such as dioxins / furans contained in the flue gas of the CONSTEEL electric furnace are completely burned and decomposed, it is necessary to continuously spray and burn a certain amount of combustible gas to increase the flue gas temperature of the CONSTEEL electric furnace (>800℃), which increases the cost of CONSTEEL electric furnace steelmaking to a certain extent.

[0005] 3. This CONSTEEL electric furnace flue gas purification process loses a large amount of waste heat in the electric furnace flue gas; in addition, it consumes a large amount of water; and causes the "smoke plume" problem.

[0006] 4. When the CONSTEEL electric furnace is at the peak of oxygen blowing smelting, the high-temperature flue gas is very hot. In the process of passing through the scrap steel continuous preheating device, the scrap steel preheating temperature is often too high, resulting in the scrap steel becoming soft and sticky (or because there are certain low-temperature alloy substances in the scrap steel), which has a certain impact on the stable operation of the scrap steel continuous preheating and conveying device. Summary of the invention

[0014] The technical problem to be solved by the present invention is to overcome the defects of the prior art. The present invention proposes a pure dry purification treatment system and treatment method for electric furnace flue gas, which can avoid the sticking of scrap steel continuously preheated by the CONSTEEL electric furnace caused by the flue gas at too high a temperature, take into account the decomposition of dioxins / furans contained in the flue gas of the electric furnace and avoid their re-synthesis, while avoiding the occurrence of the "smoke plume" problem.

[0015] In order to solve the above technical problems, the technical solution adopted by the present invention is: a pure dry purification system for electric furnace flue gas, comprising an electric furnace, a continuous preheating device, a mixed combustion settling cylinder, a waste heat boiler and a dust collector connected in sequence,

[0016] The electric furnace and the mixed combustion settling cylinder are connected by a first extraction pipeline, and the continuous preheating device and the mixed combustion settling cylinder are connected by a second extraction pipeline, and the output ends of the first extraction pipeline and the second extraction pipeline are fixed at different positions based on the upper section of the mixed combustion settling cylinder;

[0017] The waste heat boiler receives the high-temperature flue gas output from the mixed combustion settling cylinder, diverts the high-temperature flue gas and cooling water to complete the heat exchange process with a heat transfer medium, and then merges them into a bag-type dust collector to complete the dust removal process and then discharge them from the chimney.

[0018] Furthermore, the output end of the second extraction pipe is connected and communicated with the top of the mixed combustion settling cylinder, and a second regulating valve for regulating the on and off of the second extraction pipe is arranged on the second extraction pipe. The output end of the first extraction pipe is connected and communicated with the mixed combustion settling cylinder based on the side of the upper section of the mixed combustion settling cylinder, and a first regulating valve for regulating the on and off of the first extraction pipe is arranged on the first extraction pipe. An auxiliary burner is fixedly arranged on the side wall of the mixed combustion settling cylinder below the output end of the first extraction pipe.

[0019] Furthermore, the mixed combustion settling cylinder includes a first chamber and a settling ash hopper, the settling ash hopper is fixedly arranged below the first chamber, the width of the settling ash hopper is greater than the width of the first chamber, and the lower end of the first chamber is smoothly connected with the upper edge of the settling ash hopper.

[0020] Furthermore, the waste heat boiler includes a main smoke inlet pipe, a boiler body and a main smoke outlet pipe, the main smoke inlet pipe and the main smoke outlet pipe are fixedly arranged at both ends of the boiler body, and a dry ice descaling device is also arranged on the main smoke outlet pipe, the dry ice descaling device and the boiler body are located on the same axis, and the dry ice descaling device can move vertically to the inside of the boiler body.

[0021] Furthermore, there are multiple boiler furnace bodies, which include a cluster sleeve and nozzles located at both ends of the cluster sleeve. The cluster sleeve is composed of an inner tube and an outer tube, and a spacing rib is fixedly arranged between the inner tube and the outer tube. The nozzles are fixedly arranged at both ends of the inner tube. High-temperature flue gas flows in the inner tube, and cooling water flows in the gap between the inner tube and the outer tube.

[0022] Furthermore, the number of the dry ice descaling devices is the same as that of the boiler body, and the dry ice descaling devices include a driving device and a spray head fixedly arranged at a certain distance below the driving device, and the spray head can reciprocate along the length direction of the inner tube with the driving device; the spray head uses a dry ice sending device to transport block or spherical dry ice to it;

[0023] The spray head is fixedly arranged below the driving device with a dry ice descaling rod, and also includes a conveying channel for conveying dry ice, wherein the conveying channel is arranged in the dry ice descaling rod based on the length direction of the dry ice descaling rod.

[0024] Furthermore, the dust collector includes a plurality of bag-type dust collectors, which are arranged in a transverse direction and combined into one body, and adjacent bag-type dust collectors are connected and communicated with each other.

[0025] Furthermore, the waste heat boiler and the dust collector are connected by an electric furnace flue gas main pipeline, and a flue gas temperature detection device is arranged on the electric furnace flue gas main pipeline;

[0026] The output end of the dust collector is connected with a fan and a chimney in sequence.

[0027] Also includes a first pipeline and a second pipeline;

[0028] One end of the first pipeline is connected between the flue gas temperature detection device and the input end of the dust collector, and the other end is connected between the output end of the dust collector and the fan, and a first differential pressure detection device is arranged on the first pipeline;

[0029] One end of the second pipe is connected between the flue gas temperature detection device and the input end of the dust collector, and the second pipe is provided with the same number of test branches as the bag-type dust collectors, and each of the test branches is provided with a second differential pressure detection device.

[0030] Furthermore, a pneumatic conveying device is fixedly installed at the lower end of the mixed combustion settling cylinder, the waste heat boiler and each of the bag-type dust collectors, for conveying the accumulated ash in the bag-type dust collectors to a centralized ash storage.

[0031] Furthermore, a method for treating electric furnace flue gas by pure dry method is provided, which uses an electric furnace flue gas by pure dry method treatment system, and comprises the following steps:

[0032] S1. extracting the electric furnace flue gas in the electric furnace and the preheated flue gas in the continuous preheating device to mix to obtain mixed flue gas, wherein the temperature of the high-temperature flue gas is not less than 800° C., and the temperature of the preheated flue gas is 450-650° C.;

[0033] S2. The obtained mixed flue gas is retained and burned in the mixed combustion settling tube at an environment of not less than 800°C for 2-3 seconds;

[0034] S3, the obtained high-temperature flue gas is diverted from the waste heat boiler to the boiler body, and then merged and discharged after non-contact heat exchange with cooling water;

[0035] S4. The flue gas is dedusted in the dust collector and then flows to the chimney and is discharged into the atmosphere.

[0036] Compared with the prior art, the beneficial effects of the present invention include:

[0037] 1) The high-temperature electric furnace flue gas in the electric furnace is extracted into the mixed combustion settling cylinder through the added first extraction pipeline, and after being mixed with the preheated flue gas from the continuous preheating device, the flue gas temperature is maintained at not less than 800°C under the action of the auxiliary burner, and is retained in the mixed combustion settling cylinder for 2-3 seconds to ensure that the dioxins / furans and other toxic substances contained in the flue gas are burned and decomposed, and the high-temperature mixed flue gas is rapidly cooled by the waste heat boiler, which effectively avoids the re-synthesis of toxic substances;

[0038] 2) By adding a first extraction pipe on the electric furnace, the high-temperature flue gas inside the electric furnace is extracted, which can appropriately reduce the temperature inside the electric furnace, thereby effectively avoiding the problem of sticking of scrap steel charge in the electric furnace scrap steel continuous preheating device due to excessively high flue gas temperature;

[0039] 3) Through the cluster sleeves arranged in the boiler furnace, the high-temperature flue gas and the cooling water are located in different areas of the cluster sleeves and complete the heat exchange, which effectively recovers the flue gas waste heat of the high-temperature flue gas without causing heat waste of the high-temperature flue gas. In addition, there is no contact between the high-temperature flue gas and the cooling water during the heat exchange process, so that during the flue gas cooling process, the cooling water will not be mixed with the flue gas even if it is gasified, thereby effectively avoiding the "smoke plume" problem. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The disclosure of the present invention is described with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. In the accompanying drawings, the same reference numerals are used to refer to the same components. Among them:

[0041] Figure 1The overall structure of the pure dry purification system for electric furnace flue gas is schematically shown;

[0042] Figure 2 The overall structure of the waste heat boiler is shown schematically;

[0043] Figure 3 The cross-sectional structure of the boiler furnace is schematically shown;

[0044] Figure 4 The transverse cross-sectional structure of the cluster sleeve is schematically shown;

[0045] Figure 5 The overall structure of the dry ice descaling device is schematically shown.

[0046] Numbers in the figure: 1-electric furnace, 2-continuous preheating device, 3-mixed combustion settling cylinder, 4-waste heat boiler, 5-dust collector, 6-first extraction pipeline, 7-second extraction pipeline, 8-first regulating valve, 9-second regulating valve, 10-auxiliary burner, 11-first chamber, 12-settling ash hopper, 13-main smoke inlet pipe, 14-main smoke outlet pipe, 15-boiler body, 16-inner pipe, 17-outer pipe, 18-nozzle, 19 - fixed-distance ribs, 20 - dry ice descaling device, 21 - driving device, 22 - injection head, 23 - dry ice sending device, 24 - dry ice descaling rod, 25 - bag-type dust collector, 26 - electric furnace flue gas main pipeline, 27 - flue gas temperature detection device, 28 - fan, 29 - chimney, 30 - first pipeline, 31 - second pipeline, 32 - first differential pressure detection device, 33 - second differential pressure detection device, 34 - pneumatic conveying device. DETAILED DESCRIPTION

[0047] It is easy to understand that according to the technical solution of the present invention, without changing the essential spirit of the present invention, a person skilled in the art can propose a variety of interchangeable structural modes and implementation modes. Therefore, the following specific implementation modes and drawings are only exemplary descriptions of the technical solution of the present invention, and should not be regarded as the whole of the present invention or as a limitation or restriction to the technical solution of the present invention.

[0048] Figure 1 The overall structure of the pure dry method for purifying and treating the flue gas from an electric furnace is schematically shown. Figure 1As shown, it includes an electric furnace 1, a continuous preheating device 2, a mixed combustion settling cylinder 3, a waste heat boiler 4 and a dust collector 5 which are connected in sequence. The electric furnace 1 and the mixed combustion settling cylinder 3 are connected by a first extraction pipe 6, and the continuous preheating device 2 and the mixed combustion settling cylinder 3 are connected by a second extraction pipe 7. The output ends of the first extraction pipe 6 and the second extraction pipe 7 are fixed based on different positions of the upper section of the mixed combustion settling cylinder 3, that is, the electric furnace flue gas in the electric furnace 1 and the preheating flue gas in the continuous preheating device 2 are input into the mixed combustion settling cylinder 3 from different input ends to facilitate the mixing between the electric furnace flue gas and the preheating flue gas. Specifically, the output end of the aforementioned second extraction pipeline 7 is connected and connected with the top of the mixed combustion settling cylinder 3, and a second regulating valve 9 for regulating its on and off is arranged on the second extraction pipeline 7; the output end of the first extraction pipeline 6 is connected and connected with the mixed combustion settling cylinder 3 based on the side of the upper section of the mixed combustion settling cylinder 3, and a first regulating valve 8 for regulating its on and off is arranged on the first extraction pipeline 6, and an auxiliary burner 10 is fixedly arranged on the side wall of the mixed combustion settling cylinder 3 below the output end of the first extraction pipeline 6. It is worth noting that the aforementioned first regulating valve 8 and the second regulating valve 9 are both opened and closed by PLC to regulate the mixing ratio of the electric furnace flue gas and the preheating flue gas with the mixed combustion settling cylinder 3.

[0049] When the electric furnace 1 is in operation, the extracted flue gas is divided into two paths, namely, the electric furnace flue gas located in the first extraction pipe 6 and the preheating flue gas located in the second extraction pipe 7, wherein the preheating flue gas preheats the scrap steel in the continuous preheating device 2, and the temperature of the preheating flue gas is 450-650°C, which is lower than the decomposition temperature of dioxins, so that a lot of dioxins in the preheating flue gas are not fully burned and decomposed, and are still retained in the electric furnace flue gas. Therefore, after the preheating flue gas is introduced into the mixed combustion settling cylinder 3 through the second extraction pipe 7, the electric furnace flue gas (temperature>800°C) is drawn through the first extraction pipe 6 and injected into the mixed combustion settling cylinder 3 in a certain proportion, and the electric furnace flue gas can increase the temperature of the mixed flue gas after mixing with the preheating flue gas, thereby facilitating the ignition of the mixed flue gas, thereby removing the dioxins in the flue gas. After the electric furnace flue gas is mixed with the preheated flue gas, the auxiliary burner 10 is set to ensure that the flue gas temperature in the mixed combustion settling tube 3 is not less than 800°C and stays and burns in the mixed combustion settling tube 3 for 2-3 seconds, thereby ensuring that toxic substances such as dioxins / furans contained in the mixed flue gas are effectively incinerated and decomposed by high temperature, and reducing the consumption of combustible gas in the auxiliary burner 10, effectively reducing the steelmaking cost of the CONSTEEL electric furnace 1.

[0050] The aforementioned mixed flue gas flows into the waste heat boiler 4 for rapid cooling, and the impurities in the mixed flue gas and the impurities generated by combustion fall directly to the bottom of the combustion settling tube. During the rapid cooling process, if the rapid cooling effect is not good, the heavy metal dust in the impurities will catalyze the substances in the flue gas to regenerate a part of dioxins. Therefore, the mixed flue gas is burned in the combustion settling tube, and the impurities in the mixed flue gas (ash containing heavy metal dust) and the impurities generated by combustion fall directly to the bottom of the combustion settling tube, which can preliminarily remove the impurities in the flue gas, reduce the heavy metal dust in the mixed flue gas during the rapid cooling process, and thus reduce the amount of dioxin regeneration during the rapid cooling process. Therefore, it is only necessary to ensure the rapid cooling effect of the mixed flue gas and rapidly cool it to a temperature less than 200°C to effectively avoid the reaction temperature range of dioxins (300-500°C).

[0051] It is worth mentioning that the aforementioned mixed combustion settling cylinder 3 includes a first chamber 11 and a settling ash hopper 12. The settling ash hopper 12 is fixedly arranged below the first chamber 11. The width of the settling ash hopper 12 is greater than the width of the first chamber 11, and the lower end of the first chamber 11 is smoothly connected with the upper edge of the settling ash hopper 12, that is, the part opposite to the connection between the lower end of the first chamber 11 and the upper edge of the settling ash hopper 12 is a separate settling hopper 12. The structure of the first chamber 11 and the settling ash hopper 12 forms a vertical bending structure, which can effectively affect the movement trajectory of the mixed flue gas in the mixed combustion settling cylinder 3, and is conducive to the falling of debris mixed in the mixed flue gas into the settling ash hopper 12.

[0052] In order to ensure the rapid cooling effect of the flue gas input from the mixed combustion settling tube 3 to the waste heat boiler 4, Figure 2 As shown, the waste heat boiler 4 includes a main smoke inlet pipe 13, a boiler furnace 15 and a main smoke outlet pipe 14, wherein the main smoke inlet pipe 13 and the main smoke outlet pipe 14 are fixedly arranged at both ends of the boiler furnace 15. After the high-temperature mixed flue gas from the mixed combustion settling cylinder 3 enters the waste heat boiler 4 from the main smoke inlet pipe 13, it enters several boiler furnaces 15 located between the main smoke inlet pipe 13 and the main smoke outlet pipe 14 after diversion. Compared with directly quenching the entire high-temperature mixed flue gas, the high-temperature mixed flue gas is dispersed into several boiler furnaces 15 in the form of diversion, and the difficulty of quenching is significantly reduced, and the quenching effect can be significantly enhanced. The mixed flue gas after quenching is combined in the main smoke outlet pipe 14 and then output.

[0053] The aforementioned rapid cooling process is mainly carried out in the boiler furnace 15, which is essentially a heat exchange process. Figure 3-4As shown, the boiler body 15 includes a cluster sleeve and nozzles 18 located at both ends of the cluster sleeve. The cluster sleeve is composed of an inner tube 16 and an outer tube 17, and a spacing rib plate 19 is fixedly arranged between the inner tube 16 and the outer tube 17 to ensure the gap width between the inner tube 16 and the outer tube 17 while supporting the inner tube 16 and the outer tube 17. The nozzles 18 are fixedly arranged at both ends of the inner tube 16, and the high-temperature flue gas flows in the inner tube 16, and the cooling water flows in the gap between the inner tube 16 and the outer tube 17. In order to facilitate the circulation of cooling water, an upper pipe header and a lower pipe header are also arranged on the boiler furnace body 15, wherein the upper pipe header is fixedly arranged based on the nozzle 18 and the outer tube 17 at the upper end of the boiler furnace body 15, and the lower pipe header is fixedly arranged based on the nozzle 18 and the outer tube 17 at the lower end of the boiler furnace body 15, and the cooling water is input into the lower pipe header through a separate pipeline, and the cooling water is output from the upper pipe header; in order to reduce the number of the aforementioned pipelines, the upper pipe headers of multiple boiler furnace bodies 15 can be connected, and the lower pipe headers of multiple boiler furnace bodies 15 can be connected, and the cooling water is circulated in the aforementioned gap in a parallel manner. Through the arrangement of the aforementioned clustered sleeve, the contact between cooling water (such as cooling water) and the mixed flue gas can be effectively avoided. On the one hand, it can avoid the contact between water and the mixed flue gas, thereby causing the consumption of cooling water; on the other hand, a large amount of waste heat of the mixed flue gas can be recovered.

[0054] The high temperature flue gas of the CONSTEEL electric furnace 1 is divided into multiple flue gas columns, which are passed through the boiler body 15 with a smaller cross section, so as to achieve rapid cooling and waste heat recovery of the high temperature flue gas of the electric furnace 1, and effectively control the re-synthesis of dioxins in the flue gas. However, in the process of rapid cooling of the high-temperature mixed flue gas, it is inevitable that new debris in the mixed flue gas will fall into the waste heat boiler 4, and the debris will adhere to the waste heat boiler 4 to form ash accumulation. The existence of ash accumulation will inevitably affect the subsequent rapid cooling effect of the mixed flue gas. Therefore, it is necessary to regularly clean the ash accumulation inside the waste heat boiler 4. Therefore, the waste heat boiler 4 also includes a dry ice descaling device 20. The dry ice descaling device 20 is arranged on the main smoke outlet pipe 14, and the dry ice descaling device 20 and the boiler furnace body 15 are located on the same axis, and the dry ice descaling device 20 can move vertically to the inside of the boiler furnace body 15 to complete the cleaning of the ash accumulation on the inner wall of the boiler furnace body 15. The cleaning process of the aforementioned dry ice descaling device 20 can be controlled by PLC.

[0055] Figure 5 The overall structure of the dry ice descaling device is shown schematically. Figure 5The dry ice descaling device 20 is described in detail. The number of dry ice descaling devices 20 is the same as that of the boiler furnace body 15, and it includes a driving device 21 and an injection head 22 fixedly arranged at a certain distance below the driving device 21. The injection head 22 can reciprocate along the length direction of the inner tube 16 with the driving device 21, and a guide rail frame can be used to guide the driving device 21 to move along the length direction of the guide rail frame. The guide rail frame is arranged above the main smoke outlet pipe 14 parallel to the length direction of the boiler furnace body 15. The aforementioned injection head 22 can be fixedly arranged below the driving device 21 with a dry ice descaling rod 24. The driving device 21 can drive the dry ice descaling rod 24 to rotate, and the injection head 22 fixed on the dry ice descaling rod 24 can rotate synchronously with the rotation of the dry ice descaling rod 24. During the descaling process of the inner wall of the inner tube 16, if the aforementioned injection head 22 is only directed in a fixed direction, that is, it can descaling one side of the inner wall of the inner tube 16, but it is difficult to achieve descaling on the other side due to its direction problem. Therefore, it is necessary to give the injection head 22 the function of rotating so as to adjust its direction and complete the descaling process of the inner wall of the inner tube 16. This is achieved by arranging a servo motor and a transmission device on the driving device 21.

[0056] The aforementioned spray head 22 uses a dry ice delivery device 23 to deliver dry ice to it. By opening a delivery channel in the aforementioned dry ice descaling rod 24 along its length direction, one end of the delivery channel is connected to the output end of the dry ice delivery device 23, and the other end is connected to the input end of the spray head 22. The dry ice delivery device 23 ejects block or spherical dry ice from the spray head 22 through the delivery channel under the push of nitrogen, thereby contacting the inner wall of the inner tube 16, so that the dust attached thereto is frozen and brittle, and is peeled off on the inner wall of the inner tube 16 under the action of dry ice. The cleaning efficiency is high and does not involve any chemical solvents and water, effectively avoiding dust accumulation and structure. At the same time, in some embodiments, in order to ensure that the temperature of the aforementioned dry ice descaling rod 24 is constant, a circulation pipeline can be provided therein to pass cooling water to ensure that the temperature of the dry ice descaling rod 24 is constant. And the inner diameter of the aforementioned dry ice descaling rod 24 is smaller than the inner diameter of the inner tube 16.

[0057] The following combination Figure 1 The dust collector 5 is specifically described. The dust collector 5 includes a plurality of bag-type dust collectors 25. The plurality of bag-type dust collectors 25 are arranged in a horizontal direction and combined into one body. Adjacent bag-type dust collectors 25 are connected and penetrated. An air inlet and an air outlet are respectively provided at the head and tail sides of the aforementioned dust collector 5. Specifically, the air inlet is provided on a side of a bag-type dust collector 25 close to the waste heat boiler 4, and the air outlet is provided on a side of a bag-type dust collector 25 farthest from the waste heat boiler 4, so that the mixed flue gas entering the dust collector 5 can complete multi-stage adsorption of debris based on multiple bag-type dust collectors 25, and the resulting flue gas can meet the requirements of direct emission.

[0058] The aforementioned waste heat boiler 4 and the dust collector 5 are connected by an electric furnace flue gas main pipeline 26, and a flue gas temperature detection device 27 is arranged on the electric furnace flue gas main pipeline 26, which is used to detect the temperature data of the mixed flue gas input from the waste heat boiler 4 to the dust collector 5, and upload the detected temperature data to the PLC for judgment and storage. On the one hand, it can be judged whether the temperature of the mixed flue gas input to the dust collector 5 meets the requirements of its long-term operation, and on the other hand, it can be judged The rapid cooling effect of the waste heat boiler 4 is determined to determine whether it is necessary to perform descaling operations on the inside of the waste heat boiler 4. A fan 28 and a chimney 29 are connected to the output end of the dust collector 5 in sequence, which is used to discharge the mixed flue gas after the dust removal process into the atmosphere through the chimney 29.

[0059] The aforementioned dust collector 5 also includes a first pipe 30 and a second pipe 31; one end of the first pipe 30 is connected between the flue gas temperature detection device 27 and the input end of the dust collector 5, and the other end is connected between the output end of the dust collector 5 and the fan 28, and a first differential pressure detection device 32 is arranged on the first pipe 30; one end of the second pipe 31 is connected between the flue gas temperature detection device 27 and the input end of the dust collector 5, and the same number of test branches as the bag-type dust collector 25 are arranged on the second pipe 31, and a second differential pressure detection device 33 is arranged on each test branch. The aforementioned first differential pressure detection device 32 and the second differential pressure detection device 33 are used to detect the differential pressure data before and after the mixed flue gas flows through the dust collector 5 and each bag-type dust collector 25. If the differential pressure data before and after the mixed flue gas flows through the dust collector 5 or a bag-type dust collector 25 is too large, it means that the bag-type dust collector 25 is blocked and needs to be cleaned and maintained. By setting the aforementioned first differential pressure detection device 32 and the second differential pressure detection device 33, the blockage of each bag-type dust collector 25 can be known in real time and in a timely manner. The differential pressure data obtained by the aforementioned first differential pressure detection device 32 and the second differential pressure detection device 33 are transmitted to the PLC in real time for judgment and storage, and the PLC can also take into account the operation process of the electric furnace 1, the continuous preheating device 2, the mixed combustion settling cylinder 3, the waste heat boiler 4 and the dust collector 5, and regulate the subsequent emission process.

[0060] It is worth mentioning that an ash bin is also included. A pneumatic conveying device 34 is fixedly installed at the lower end of the mixed combustion settling cylinder 3, the waste heat boiler 4 and each bag-type dust collector 25, which is used to transport the accumulated ash in the bag-type dust collector 25 to the centralized ash bin for collection.

[0061] The technical scope of the present invention is not limited to the contents in the above description. Those skilled in the art can make various deformations and modifications to the above embodiments without departing from the technical idea of ​​the present invention, and these deformations and modifications should all fall within the protection scope of the present invention.

Claims

1. A pure dry purification system for electric furnace flue gas, characterized in that: It comprises an electric furnace (1), a continuous preheating device (2), a mixed combustion settling cylinder (3), a waste heat boiler (4) and a dust collector (5) which are connected in sequence. The electric furnace (1) and the mixed combustion settling cylinder (3) are connected via a first extraction pipeline (6), and the continuous preheating device (2) and the mixed combustion settling cylinder (3) are connected via a second extraction pipeline (7), and the output ends of the first extraction pipeline (6) and the second extraction pipeline (7) are fixed at different positions based on the upper section of the mixed combustion settling cylinder (3); The waste heat boiler (4) receives the high-temperature flue gas output from the mixed combustion settling cylinder (3), diverts the high-temperature flue gas and cooling water to complete the heat exchange process with a heat-conducting medium, and then merges them into a bag-type dust collector (25) to complete the dust removal process and then discharge them from a chimney (29).

2. The electric furnace flue gas pure dry purification system according to claim 1 is characterized in that: The output end of the second extraction pipe (7) is connected to and communicates with the top of the mixed combustion settling cylinder (3), and a second regulating valve (9) for regulating the on-off of the second extraction pipe (7) is arranged on the second extraction pipe (7). The output end of the first extraction pipe (6) is connected to and communicates with the mixed combustion settling cylinder (3) based on the side of the upper section of the mixed combustion settling cylinder (3), and a first regulating valve (8) for regulating the on-off of the first extraction pipe (6) is arranged on the first extraction pipe (6). An auxiliary burner (10) is fixedly arranged on the side wall of the mixed combustion settling cylinder (3) below the output end of the first extraction pipe (6).

3. The electric furnace flue gas pure dry purification treatment system according to claim 2 is characterized in that: The mixed combustion settling cylinder (3) comprises a first chamber (11) and a settling ash hopper (12); the settling ash hopper (12) is fixedly arranged below the first chamber (11); the width of the settling ash hopper (12) is greater than the width of the first chamber (11); the lower end of the first chamber (11) is smoothly connected to the upper edge of the settling ash hopper (12).

4. The electric furnace flue gas pure dry purification treatment system according to claim 1 is characterized in that: The waste heat boiler (4) comprises a main smoke inlet pipe (13), a boiler furnace body (15) and a main smoke outlet pipe (14); the main smoke inlet pipe (13) and the main smoke outlet pipe (14) are fixedly arranged at two ends of the boiler furnace body (15); a dry ice descaling device (20) is also arranged on the main smoke outlet pipe (14); the dry ice descaling device (20) and the boiler furnace body (15) are located on the same axis, and the dry ice descaling device (20) can move vertically to the inside of the boiler furnace body (15).

5. The electric furnace flue gas pure dry purification system according to claim 4 is characterized in that: The boiler furnace body (15) is multiple, and the boiler furnace body (15) includes a clustering sleeve and nozzles (18) located at both ends of the clustering sleeve. The clustering sleeve is composed of an inner tube (16) and an outer tube (17), and a spacing rib plate (19) is fixedly arranged between the inner tube (16) and the outer tube (17). The nozzles (18) are fixedly arranged at both ends of the inner tube (16). High-temperature flue gas flows in the inner tube (16), and cooling water flows in the gap between the inner tube (16) and the outer tube (17).

6. The electric furnace flue gas pure dry purification treatment system according to claim 5, characterized in that: The number of the dry ice descaling devices (20) is the same as that of the boiler furnace body (15). The dry ice descaling devices (20) include a driving device (21) and a spray head (22) fixedly arranged at a certain distance below the driving device (21). The spray head (22) can reciprocate along the length direction of the inner tube (16) with the driving device (21); the spray head (22) uses a dry ice sending device (23) to transport block or spherical dry ice to it; The spray head (22) is fixedly arranged below the driving device (21) with a dry ice descaling rod (24), and also includes a conveying channel for conveying dry ice, wherein the conveying channel is arranged in the dry ice descaling rod (24) based on the length direction of the dry ice descaling rod (24).

7. The electric furnace flue gas pure dry purification system according to claim 1, characterized in that: The dust collector (5) comprises a plurality of bag-type dust collectors (25), wherein the plurality of bag-type dust collectors (25) are arranged in a transverse direction and combined into one body, and adjacent bag-type dust collectors (25) are connected and communicated with each other.

8. The electric furnace flue gas pure dry purification system according to claim 7, characterized in that: The waste heat boiler (4) and the dust collector (5) are connected via an electric furnace flue gas main pipeline (26), and a flue gas temperature detection device (27) is provided on the electric furnace flue gas main pipeline (26); The output end of the dust collector (5) is connected in sequence to a fan (28) and a chimney (29). It also includes a first pipeline (30) and a second pipeline (31); One end of the first pipeline (30) is connected between the flue gas temperature detection device (27) and the input end of the dust collector (5), and the other end is connected between the output end of the dust collector (5) and the fan (28), and a first differential pressure detection device (32) is arranged on the first pipeline (30); One end of the second pipe (31) is connected between the flue gas temperature detection device (27) and the input end of the dust collector (5), and the same number of test branches as the bag-type dust collector (25) are arranged on the second pipe (31), and a second differential pressure detection device (33) is arranged on each of the test branches.

9. The electric furnace flue gas pure dry purification system according to claim 7, characterized in that: A pneumatic conveying device (34) is fixedly provided at the lower end of the mixed combustion settling cylinder (3), the waste heat boiler (4) and each bag-type dust collector (25) for conveying the accumulated ash in the bag-type dust collector (25) to a centralized ash storage.

10. A pure dry purification method for electric furnace flue gas, characterized in that: The electric furnace flue gas pure dry purification treatment system according to any one of claims 1 to 9 comprises the following steps: S1, extracting and mixing the electric furnace flue gas in the electric furnace (1) and the preheated flue gas in the continuous preheating device (2) to obtain mixed flue gas, wherein the temperature of the high-temperature flue gas is not less than 800° C., and the temperature of the preheated flue gas is 450-650° C.; S2, the obtained mixed flue gas is retained and burned in the mixed combustion settling tube (3) at an environment of not less than 800°C for 2-3 seconds; S3, the obtained high-temperature flue gas is diverted from the waste heat boiler (4) to the boiler body (15), where it is combined with cooling water for discharge after non-contact heat exchange is completed; S4. The obtained flue gas is dedusted in the dust collector (5) and then flows to the chimney (29) and is discharged into the atmosphere.

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